Zobrazení zdroje stránky Cliffordhenneberg4593

Hydroxylation and debromination HBCD metabolites were identified. In addition, the different EFs of HBCDs in cells and mediums suggested the selective transfer of chiral HBCDs and HBCD metabolites through the cell membrane. This study provided new insight into the enantiomer-selective metabolism of HBCDs.Sulfuric acid formed by pyrite oxidation and nitric acid formed by oxidation of reducing nitrogen fertilizer through neutralization with carbonate minerals can rapidly perturb the carbon cycle. However, these processes and corresponding mechanisms have not been well documented due to the lack of information about both the sources of acids and the processes of oxidative weathering. Here, multiple isotopes (13C-DIC, 34S and 18O-SO42-, 15N and 18O-NO3-, and 18O and D-H2O), hydrochemistry and historical monitoring data were used to assess the roles of strong acids in chemical weathering and the carbon cycle in a karst river system. The variations in alkalinity and the δ13C-DIC signals, along with theoretical mixing models, indicated that strong acids were involved in carbonate weathering. However, the contribution of weathering driven by strong acids to the total weathering budget determined by mixing models was lower than that determined by assuming that all protons were neutralized by minerals. These protons were liberated from oxidation of pyrite and reducing nitrogen fertilizers constrained by isotope techniques and hydrochemistry with the use of a Bayesian isotope mixing model. The strong acid weathering could account for 66% of total weathering if all of the protons were neutralized by carbonate and silicate, which was not consistent with the result provided by mixing models. These results indicated that in addition to being neutralized by minerals, the protons might be largely neutralized by HCO3- derived from rock weathering driven by both carbonic and strong acids. The coupling cycles of carbon, nitrogen and sulfur would be boosted due to oxidation of pyrite and reducing nitrogen fertilizers. This study suggests that the CO2 uptake by terrestrial chemical weathering should be re-evaluated after adequately considering the effects of strong acids liberated by natural processes and anthropogenic activities.Transitional coastal zones are subject to high degrees of temporal fluctuation in environmental conditions, with these patterns varying in space. Gaining an in depth understanding of how sessile organisms cope with and respond to such environmental changes at multiple scales is needed to i) advance fundamental knowledge, ii) predict how organisms may react to stressors and iii) support the management of halieutic resources in transitional coastal areas. We addressed this question using mussels (Mytilus galloprovincialis) as model system. Valve-gaping sensor were deployed at multiple sites within the southern Venice Lagoon over a period of 6 months, to investigate the existence of periodicity in valve-gaping and its relationship with environmental variables, such as temperature and chlorophyll-a. Gaping behaviour was found to have periodic rhythms, of ~12 h and ~ 24 h, which were most pronounced in the inner part of lagoon part and were strongest during summer months. In autumn, the dual periodicity became weaker and mostly the 12 h remained. Gaping was closely linked with tide, but the relationship in terms of phasing varied upon location. Surprisingly, no clear direct relationships were found with chlorophyll-a, but food delivery may be mediated by tide itself. The results highlight the heterogeneity of behaviour and the endogenic nature of circadian rhythms in space and time. These findings have important implications for management of transitional areas where tidal alteration may have impacts on key behaviours, and emphasize the importance of characterizing their rhythms before using these as stress indicator. Moreover, the described tidal relationships should be included in growth models of bivalves in these systems.Globally, ambient air pollution claims ~9 million lives yearly, prompting researchers to investigate changes in air quality. Of special interest is the impact of COVID-19 lockdown. Many studies reported substantial improvements in air quality during lockdowns compared with pre-lockdown or as compared with baseline values. Since the lockdown period coincided with the onset of the rainy season in some tropical countries such as Nigeria, it is unclear if such improvements can be fully attributed to the lockdown. [https://www.selleckchem.com/products/senaparib.html find more] We investigate whether significant changes in air quality in Nigeria occurred primarily due to statewide COVID-19 lockdown. We applied a neural network approach to derive monthly average ground-level fine aerosol optical depth (AODf) across Nigeria from year 2001-2020, using the Multi-angle Implementation of Atmospheric Correction (MAIAC) AODs from Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) satellites, AERONET aerosol optical properties, meteorological and spatial parameters. During the year 2020, we found a 21% or 26% decline in average AODf level across Nigeria during lockdown (April) as compared to pre-lockdown (March), or during the easing phase-1 (May) as compared to lockdown, respectively. Throughout the 20-year period, AODf levels were highest in January and lowest in May or June, but not April. Comparison of AODf levels between 2020 and 2019 shows a small decline (1%) in pollution level in April of 2020 compare to 2019. Using a linear time-lag model to compare changes in AODf levels for similar months from 2002 to 2020, we found no significant difference (Levene's test and ANCOVA; α = 0.05) in the pollution levels by year, which indicates that the lockdown did not significantly improve air quality in Nigeria. Impact analysis using multiple linear regression revealed that favorable meteorological conditions due to seasonal change in temperature, relative humidity, planetary boundary layer height, wind speed and rainfall improved air quality during the lockdown.Depletion of groundwater is accelerated due to an increase in water demand for applications in urbanized areas, agriculture sectors, and energy extraction, and dwindling surface water during changing climate. Managed aquifer recharge (MAR) is one of the several methods that can help achieve long-term water sustainability by increasing the natural recharge of groundwater reservoirs with water from non-traditional supplies such as excess surface water, stormwater, and treated wastewater. Despite the multiple benefits of MAR, the wide-scale implementation of MAR is lacking, partly because of challenges to select the location for MAR implementation and identify the MAR type based on site conditions and needs. In this review, we provide an overview of MAR types with a basic framework to select and implement specific MAR at a site based on water availability and quality, land use, source type, soil, and aquifer properties. Our analysis of 1127 MAR projects shows that MAR has been predominantly implemented in sites with sandy clay loam soil (soil group C) and with access to river water for recharge.